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375ecf678c
Update the vendored TomsFastMath (TFM) library to v0.13.1. Resolves: https://bugzilla.clamav.net/show_bug.cgi?id=11992 I removed compatibility macro's from when libTomMath was used. This required removing a bunch of faux-error handling because the fast-math equivalent functions return void, and cannot fail. The previous version used had named the header "bignum_fast.h" instead of "tfm.h" and had customizations in that header to enable TFM_CHECK all the time, and also TFM_NO_ASM if __GNUC__ not defined or if the system isn't 64bit architecture. This update uses tfm.h as-is, and has CMake define TFM_CHECK and TFM_NO_ASM as needed. I've kept bignum.h as an interface to including tfm.h so that in the future we can more easily add support for system-installed TomsFastMath instead of the vendored one, taking inspiration from Debian's patch to support system-TomsFastMath. See: https://salsa.debian.org/clamav-team/clamav/-/blob/unstable/debian/patches/add-support-for-system-tomsfastmath.patch
101 lines
2.4 KiB
C
101 lines
2.4 KiB
C
/* TomsFastMath, a fast ISO C bignum library.
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*
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* This project is meant to fill in where LibTomMath
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* falls short. That is speed ;-)
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*
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* This project is public domain and free for all purposes.
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*
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* Tom St Denis, tomstdenis@gmail.com
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*/
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#include <tfm_private.h>
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/* This is possibly the mother of all prime generation functions, muahahahahaha! */
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int fp_prime_random_ex(fp_int *a, int t, int size, int flags, tfm_prime_callback cb, void *dat)
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{
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unsigned char *tmp, maskAND, maskOR_msb, maskOR_lsb;
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int res, err, bsize, maskOR_msb_offset;
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/* sanity check the input */
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if (size <= 1 || cb == NULL || t <= 0 || t > FP_PRIME_SIZE) {
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return FP_VAL;
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}
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/* TFM_PRIME_SAFE implies TFM_PRIME_BBS */
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if (flags & TFM_PRIME_SAFE) {
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flags |= TFM_PRIME_BBS;
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}
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/* calc the byte size */
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bsize = (size>>3)+(size&7?1:0);
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/* we need a buffer of bsize bytes */
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tmp = malloc(bsize);
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if (tmp == NULL) {
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return FP_MEM;
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}
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/* calc the maskAND value for the MSbyte*/
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maskAND = 0xFF >> ((8 - (size & 7)) & 7);
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/* calc the maskOR_msb */
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maskOR_msb = 0;
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maskOR_msb_offset = (size - 2) >> 3;
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if (flags & TFM_PRIME_2MSB_ON) {
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maskOR_msb |= 1 << ((size - 2) & 7);
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} else if (flags & TFM_PRIME_2MSB_OFF) {
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maskAND &= ~(1 << ((size - 2) & 7));
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}
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/* get the maskOR_lsb */
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maskOR_lsb = 1;
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if (flags & TFM_PRIME_BBS) {
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maskOR_lsb |= 3;
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}
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do {
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/* read the bytes */
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if (cb(tmp, bsize, dat) != bsize) {
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err = FP_VAL;
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goto error;
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}
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/* work over the MSbyte */
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tmp[0] &= maskAND;
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tmp[0] |= 1 << ((size - 1) & 7);
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/* mix in the maskORs */
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tmp[maskOR_msb_offset] |= maskOR_msb;
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tmp[bsize-1] |= maskOR_lsb;
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/* read it in */
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fp_read_unsigned_bin(a, tmp, bsize);
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/* is it prime? */
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res = fp_isprime_ex(a, t);
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if (res == FP_NO) continue;
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if (flags & TFM_PRIME_SAFE) {
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/* see if (a-1)/2 is prime */
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fp_sub_d(a, 1, a);
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fp_div_2(a, a);
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/* is it prime? */
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res = fp_isprime_ex(a, t);
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}
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} while (res == FP_NO);
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if (flags & TFM_PRIME_SAFE) {
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/* restore a to the original value */
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fp_mul_2(a, a);
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fp_add_d(a, 1, a);
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}
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err = FP_OKAY;
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error:
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free(tmp);
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return err;
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}
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/* $Source$ */
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/* $Revision$ */
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/* $Date$ */
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